| 1. |
- Forsén, Rikard, et al.
(författare)
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Nanostructuring and coherency strain in multicomponent hard coatings
- 2014
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Ingår i: APL Materials. - : American Institute of Physics (AIP). - 2166-532X. ; 2:11, s. 116104-
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Tidskriftsartikel (refereegranskat)abstract
- Lattice resolved and quantitative compositional characterizations of the microstructure in TiCrAlN wear resistant coatings emerging at elevated temperatures are performed to address the spinodal decomposition into nanometer-sized coherent cubic TiCr- and Al-rich domains. The domains coarsen during annealing and at 1100 ºC, the Al-rich domains include a metastable cubic Al(Cr)N phase containing 9 at.% Cr and a stable hexagonal AlN phase containing less than 1 at.% Cr. The cubic and the hexagonal phases form strained semi-coherent interfaces with each other.
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| 2. |
- Salamania, Janella, 1992-, et al.
(författare)
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Elucidating dislocation core structures in titanium nitride through high-resolution imaging and atomistic simulations
- 2022
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Ingår i: Materials & design. - : Elsevier. - 0264-1275 .- 1873-4197. ; 224
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Tidskriftsartikel (refereegranskat)abstract
- Although titanium nitride (TiN) is among the most extensively studied and thoroughly characterizedthin-film ceramic materials, detailed knowledge of relevant dislocation core structures is lacking. Byhigh-resolution scanning transmission electron microscopy (STEM) of epitaxial single crystal (001)-oriented TiN films, we identify different dislocation types and their core structures. These include, besidesthe expected primary a/2{110}h110i dislocation, Shockley partial dislocations a/6{111}h112i and sessileLomer edge dislocations a/2{100}h011i. Density-functional theory and classical interatomic potentialsimulations complement STEM observations by recovering the atomic structure of the different disloca-tion types, estimating Peierls stresses, and providing insights on the chemical bonding nature at the core.The generated models of the dislocation cores suggest locally enhanced metal–metal bonding, weakenedTi-N bonds, and N vacancy-pinning that effectively reduces the mobilities of {110}h110i and {111}h112idislocations. Our findings underscore that the presence of different dislocation types and their effects onchemical bonding should be considered in the design and interpretations of nanoscale and macroscopicproperties of TiN.
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| 3. |
- Salamania, Janella, et al.
(författare)
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Influence of nitrogen vacancies on the decomposition route and age hardening of wurtzite Ti1−xAlxNy thin films
- 2023
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : A V S AMER INST PHYSICS. - 0734-2101 .- 1520-8559. ; 41:6
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Tidskriftsartikel (refereegranskat)abstract
- The wurtzite phase of TiAlN has been known to form in industrial grade coatings with high Al content; yet, a significant knowledge gap exists regarding its behavior at high temperatures and the impact of defects on its properties. Specifically, its response to high temperatures and the implications of defects on its characteristics are poorly understood. Here, the high-temperature decomposition of nitrogen-deficient epitaxial wurtzite Ti1-xAlxNy (x = 0.79-0.98, y = 0.82-0.86) films prepared by reactive magnetron sputtering was investigated using x-ray diffractometry and high-resolution scanning transmission electron microscopy. The results show that wurtzite Ti(1-x)Al(x)Ny decomposes by forming intermediary MAX phases, which then segregate into pure c-TiN and w-AlN phases after high-temperature annealing and intermetallic TiAl nanoprecipitates. The semicoherent interfaces between the wurtzite phase and the precipitates cause age hardening of approximately 4-6 GPa, which remains even after annealing at 1200 degrees C. These findings provide insight into how nitrogen vacancies can influence the decomposition and mechanical properties of wurtzite TiAlN.
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| 4. |
- Salamania, Janella, et al.
(författare)
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Influence of pulsed-substrate bias duty cycle on the microstructure and defects of cathodic arc-deposited Ti1-xAlxN coatings
- 2021
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Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 419
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Tidskriftsartikel (refereegranskat)abstract
- The influence of pulsed substrate bias duty cycle on the growth, microstructure, and defects of Ti1-xAlxN coatings grown by cathodic arc deposition was investigated. Ti1-xAlxN coatings of varying compositions (x = 0.56, 0.38, 0.23) were deposited on cemented carbide substrates with 10, 25, 50, and 95% duty cycles of 50 V pulsed-bias under 10 Pa of pure N-2 gas. Coatings grown at low duty cycles (10 and 25%) showed strongly textured, underdense coatings with facetted columns and low amount of lattice defects. Applying higher duty cycles (50 and 95%) produced coatings that have denser microstructures, less preferred orientation, increasing compressive stresses and increased lattice defect densities. Our study elucidates how duty cycle variation not only changes the overall average energy supplied at the growth front but also kinetically influences the coating growth and thus microstructure and defect structure.
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| 5. |
- Yalamanchili, Kumar, et al.
(författare)
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Growth and Mechanical Behavior of Nanoscale Structures in ZrN/Zr0.63Al0.37N Multilayers
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Structure and mechanical properties of monolithic and nanoscale multilayers of ZrN/Zr0.63Al0.37N are investigated as a function of Zr0.63Al0.37N layer thickness. ZrN/Zr0.63Al0.37N multilayers were deposited by reactive magnetron sputtering on MgO (001) substrates at a temperature of 700 °C. Monolithic Zr0.63Al0.37N film shows a chemically segregated nanostructure of cubic-ZrN and wurtzite-AlN rich domains with incoherent interfaces. Three dimensional atom probe measurements reveal comparable chemical segregation between monolithic and multilayer Zr0.63Al0.37N film. The multilayers show systematic changes in nanostructure as a function of Zr0.63Al0.37N layer thickness resulting in mechanical properties such as hardness and fracture resistance being tunable. A maximum hardness of 34 GPa is achieved with 10 nm Zr0.63Al0.37N layer thickness having semi-coherent interfaces between wurtzite-AlN and cubic-ZrN rich domains. Higher fracture resistance is achieved at 2nm Zr0.63Al0.37N where AlN rich domains are epitaxially stabilized in the metastable cubic phase.
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| 6. |
- Aad, G, et al.
(författare)
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- 2015
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swepub:Mat__t
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